Advancing homogeneous networking principles for the development of fatigue-resistant,low-swelling and sprayable hydrogels for sealing wet,dynamic and concealed wounds in vivo

Effective sealing of wet,dynamic and concealed wounds remains a formidable challenge in clinical practice.Sprayable hydrogel sealants are promising due to their ability to cover a wide area rapidly,but they face limitations in dynamic and moist environments.To address this issue,we have employed the principle of a homogeneous network to design a sprayable hydrogel sealant with enhanced fatigue resistance and reduced swelling.This network is formed by combining the spherical structure of lysozyme(LZM)with the orthotetrahedral structure of 4-arm-polyethylene glycol(4-arm-PEG).We have achieved exceptional sprayability by controlling the pH of the precursor solution.The homogeneous network,constructed through uniform cross-linking of amino groups in protein and 4-arm-PEG-NHS,provides the hydrogel with outstanding fatigue resistance,low swelling and sustained adhesion.In vitro testing demonstrated that it could endure 2000 cycles of underwater shearing,while in vivo experiments showed adhesion maintenance exceeding 24 h.Furthermore,the hydrogel excelled in sealing leaks and promoting ulcer healing in models including porcine cardiac hemorrhage,lung air leakage and rat oral ulcers,surpassing commonly used clinical materials.Therefore,our research presents an advanced biomaterial strategy with the potential to advance the clinical management of wet,dynamic and concealed wounds.

Enlisting a Traditional Chinese Medicine to tune the gelation kinetics of a bioactive tissue adhesive for fast hemostasis or minimally invasive therapy

Gelation kinetics is important in tailoring chemically crosslinked hydrogel-based injectable adhesives for different applications.However,the regulation of gelation rate is usually limited to varying the gel precursor and/or crosslinker concentration,which cannot reach a fine level and inevitably alters the physical properties of hydrogels.Amidation reactions are widely used to synthesize hydrogel adhesives.In this work,we propose a traditional Chinese medicine(Borax)-input strategy to tune the gelation rate of amidation reaction triggered systems.Borax provides an initial basic buffer environment to promote the deprotonation process of amino groups and accelerate this reaction.By using a tissue adhesive model PEG-lysozyme(PEG-LZM),the gelation time can be modulated from seconds to minutes with varying Borax concentrations,while the physical properties remain constant.Moreover,the antibacterial ability can be improved due to the bioactivity of Borax.The hydrogel precursors can be regulated to solidify instantly to close the bleeding wound at emergency.Meanwhile,they can also be customized to match the flowing time in the catheter,thereby facilitating minimally invasive tissue sealing.Because this method is easily operated,we envision Borax adjusted amidation-type hydrogel has a promising prospect in clinical application.